Rainwater Harvesting

Water Law Resource September 5, 2012 — 1,013 views

Because having clean, potable water is crucial for cities, livestock and irrigation, scientists and agriculturalists are always on the lookout for effective ways of generating and preserving the precious liquid. Of course, one obvious supply of water is rain, whose plentitude and recurrence make it an extremely valuable source.

People have been using rainwater to nourish crops and populations for thousands of years, but recent technological advances have helped make the process of rainwater harvesting more efficient and exact than ever before.

Here are a few of the most current and effective methods for harvesting rainwater.

Rooftop rainwater

One of the most common ways to harvest rainwater - especially in third-world and developing countries - is to collect it on residential rooftops. This method is popular because it is space-efficient and provides individuals and households with their own replenishable supply of water. Many independent farmers use this technique, which combines tanks and gutters, to store water for their crops or livestock.

However, for human consumption, this water must often be filtered. This process varies by location, but is often done in a communal system.

Of course, rooftop rain collection can only be effectively carried out in regions that receive a reasonable amount of rainfall. South American and Caribbean countries are common settings, although China's use of the process is growing.

Groundwater dams

Another common method for harvesting groundwater is by using groundwater dams. These subterranean structures obstruct the natural flow of groundwater and siphon it toward underground storage facilities. In this process, water that has been absorbed by the earth's surface and entered the groundwater supply is collected and saved for future use.

There are two main advantages to utilizing groundwater dams: evaporation prevention and protection against contamination. Water collected by groundwater dams and stored underground experiences much lower levels of evaporation compared to surficial reservoirs.

Furthermore, water stored underground is much less susceptible to the risk of parasites and contamination, both of which can spread serious diseases and endanger crops and livestock.

Above-ground tanks

Many communities also utilize above-ground tanks to store water for future use. Sometimes these tanks are used to collect water harvested from rooftop devices, although they can also collect their own rainwater as well as house water that has already been filtered.

While there are many methods used for harvesting rainwater across the world, almost every country and culture uses some form of harvesting process to ensure a steady supply of agricultural and drinking water throughout the year.